Clematis

Clematis

Clematis is one of the most popular flowering vines. They bloom in almost every colour; flowers can be single or double ranging from small to large. Their shape can be tubular, star-like, flat open discs or nodding bells.

Depending on the cultivar, flowering can take place in spring and again in late summer, all summer, or in late summer through fall. Given proper support, they are easy to grow. Clematis climbs by twining slender stems (petioles) around a wire (non-rusting, either galvanized or plastic coated) or other thin supports.

They can be grown on a wall, fence, pergola, trellis, arbour, obelisk, or pole. They can also be trained to grow on trees, conifers, shrubs, or with climbing roses.

How to Grow

How to Grow

Light, wind, soil, and pH are all factors that need consideration.

Clematis should have their top growth in at least 6 hours of sun per day.

Clematis grows best in loamy, moist soils that drain well. They do not like wet feet. If the soil is heavy clay, it is a good idea to amend it before planting with coarse builder’s sand and plenty of manure or compost.

For sandy soil, add as much organic matter as possible. Keep clematis well watered at all times and never allow them to dry out.

Clematis thrives in alkaline soil (pH value more than 7). Determine your pH with a soil test kit available at any Sheridan Nurseries Garden Centre.

If the soil is extremely acidic, add lime at the time of planting. In future years, test the soil first and add dolomite when required.

Planting Tips

Planting Tips

Immerse the container in a bucket of water for an hour before planting.

Very gently remove the Clematis and its support from the container. Avoid rushing the process as stems can break easily.

Loosen the roots and place the root ball in the prepared hole with the crown (the spot where the stem meets the roots) 2.5-5 cm (1-2”) below the soil level. This allows new buds to emerge from below the ground in the event the vine is seriously damaged.

Pruning

Pruning

Clematis that bloom in April or May flower on last year’s wood. Some Clematis produce 2 flushes of blooms in spring on old wood and again in late summer on the new growth. These two groups really do not need any pruning unless they’ve become very large and unwieldy or need weak and dead stems removed. If pruning is absolutely necessary it can be done after the initial flowering.

To encourage a bushy vine with a lot of flowers, prune these clematis in early spring every year. Cut back all the old stems to the lowest pair of live buds. If not pruned this group often produces straggly plants with only a few blooms at the top.

If you do not know which type of clematis you have, bring a flower or the plant tag into your local Sheridan Nurseries Garden Centre. Our knowledgeable staff will be happy to advise as to the variety name and pruning requirements.

Maintenance

Maintenance

As plant growth becomes vigorous you can fertilize Clematis until the flower buds are just about to open, then stop feeding. This prevents the buds from opening in quick succession and prolongs the flowering period.

When the flowers are finished start fertilizing again with the Parkwood® Garden All 4-12-8 to invigorate the plant and encourage another flush of flowers, especially in the repeat flowering cultivars.

Eliminate feeding and reduce watering by September

Problems

Problems

Powdery mildew can sometimes affect Clematis. Watering in the morning is a good way to help prevent this. If the powdery mildew still appears spray with garden sulphur.

Clematis Wilt is a disease that travels rapidly and is often fatal. Symptoms include sudden wilting and collapse of either a previously healthy stem(s) or the whole plant. The wilted stems turn black. There is no effective control. You can cut stems back well below the level of infection or right to ground level. Remove the infected material immediately and do not compost it. Disinfect your pruners after cutting.